Fabrication of macroporous soft hydrogels of Chitosan scaffolds by hydrothermal reaction and cytotoxicity to 3T3 L1 cells

A novel method of fabricating a macroporous chitosan (CH) hydrogel scaffold that is partly crosslinked physically and chemically is introduced. This involved the hydrothermal reaction of chitosan in the presence of succinic acid (SA) and urea (UR) in addition to chemical crosslinking in the presence of genipin (G). The physical crosslinks could be removed by extraction with dilute sodium hydroxide, leaving a macroporous and lightly crosslinked CH that could function as a biocompatible macroporous scaffold. The structure of the product was characterized by 13C solid-state NMR, FTIR, TGA, and PXRD. The porosity of the gel was assessed by micro CT x-ray imaging, while the rheological properties were evaluated by rheometry. The gels were observed to absorb a significant quantity of water (~ 500 g/g maximum), but their rheological properties were not improved significantly as a result of the additional mild chemical crosslinking. The scaffold of the desired shape can be prepared in this method through the variation in the shape of the reacting vessel as the gel takes the shape of the container. The gels were non-toxic to 3T3 L1 (mouse fibroblast) cells and thus offer scope for both haemostatic and drug delivery applications. The constraint of the existing system, at this phase, is the lack of ability to fabricate microporous CH with higher porosity and higher surface area.